1. Field of the Invention
The present invention relates to a method and an apparatus for making a pleat in a sheet-like material.
2. Description of the Related Art
Conventionally, in order to make pleats in a fabric for a curtain, for example, and fix them by a sewing machine, there have been employed such methods as the fabric is manually supplied to a winding tool for two turns, three turns or four turns, or the fabric is sewn while it is folded manually taking measurements of the pleats according to a scale, or in case where narrow pleats are intended, the fabric is supplied manually to a sewing device through various types of guide members arranged in a row, while the fabric is gradually rounded to be folded from the fabric edge which will constitute a pleated part, or in case where the fabric is short, the total length is mechanically folded at a time and then manually supplied to the sewing device.
However, as the fabric is supplied by hand in such conventional methods, the feed to the winding tool will result in lack of symmetry due to uneveness and unsymmetry which occur in holding force for the fabric and also due to differences in coefficient of friction, thickness and flexibility of the fabric. This will cause undesirable changes in width of the finished pleat, drops of seams, lateral deflection of the pleat. Accordingly, such conventional methods may be applied only to the pleat having a fixed narrower width, but not applicable to the pleat having a larger width, or long-sized fabric. Thus, they have required complicated manual adjusting works that a skilled operator must monitor and re-adjust the feeding conditions.